The present invention relates to a stack of sheets preserving a compound or compounds being volatile at room temperature (hereinafter referred to as volatile compound) and particularly when the volatile compound is an insecticidal or aroma chemical compound.
The art in which a sheet preserves a volatile compound is well known. Such a sheet usually is placed where the surrounding environment fit the purpose of the preserved compound and is set to vaporize the preserved compound(s). However, the employment of a single sheet has limits and may be considered unsatisfactory. A large part of the preserved compound vaporizes after a relatively short period of time and cannot be efficient to vaporize the same compound for a relatively long period of time. Therefore, it would be a distinct advantage if a sheet model can vaporize the preserved compound for a long period of time. The longer vaporization period will allow the sheet model to extend its uses as an air refresher, insecticide and/or pest repellent.
The goal of the present invention is to have a stack of sheets preserving a volatile compound, to which comprise the ability to vaporize the preserved volatile compound after a relatively long period of time.
The sheets of the present invention are employed as a stack of sheets. By stacking plural sheets that preserve the volatile compound, vaporization continues after a long period of time. As the number of sheets increase, the vaporization within the sheets that preserve the volatile compound is suppressed, favorably causing the compound to continually vaporize after a long period of time. The number of sheets in the present invention is generally at least 10 sheets, for example 10 to 1000 sheets, preferably having at least 20 sheets, for example 20 to 500 sheets.
The size of the sheet preserving the volatile compound is not especially limited but the object of use, variation of sheet material, variation of the compound, and a consideration for the surrounding environment in setting may be factors influencing the size of the sheet. To generally fulfill these factors, a sheet of 20 to 1000 cm2 usually is employed. The thickness of the said sheet is also not limited, but a thickness of 20 to 200 xcexcm may be preferable.
Materials to fabricate the sheet employed in the present invention are also not especially limited, and for example, papers; synthetic resins such as polyesters and polyamides; aluminum; and so on may be employed. Furthermore, employing sheets wherein synthetic resin(s) cover(s) the surface of paper or aluminum is possible.
The compound in the present invention may be any volatile compound that has the ability to readily vaporize at room temperature or more particularly, when the vapor pressure is at least 1xc3x9710xe2x88x924 mmHg at 20xc2x0 C. Such volatile compounds may be the active ingredient found in insecticides, acaricides, noxious pest repellents that are pest controlling compounds or the active ingredient found in perfumes that are aroma chemicals.
Specific examples for insecticidal compounds recited above are N,N-diethyl-m-toluamide, carane-3,4-diol, and pyrethroid compounds such as 1-ethynyl-2-methyl-2-pentenyl (1R)-3-(2-methyl-1-propenyl)-2,2-dimethylcyclopropanecarboxylate (common name: empenthrin); 2,3,5,6-tetrafluorobenzyl (1R)-trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropanecarboxylate (common name: transfluthrin); 1-ethynyl-2-methyl-2-pentenyl 3-(2-chloro-2-fluorovinyl)-2,2-dimethylcyclopropanecarboxylate; 2,3,5,6-tetrafluoro-4-methylbenzyl 3-(2-methyl-1-propenyl)-2,2-dimethylcyclopropanecarboxylate; 2,3,5,6-tetrafluoro-4-methylbenzyl 3-(2-chloro-2-fluorovinyl)-2,2-dimethylcyclopropanecarboxylate; and 2,3,5,6-tetrafluoro-4-methylbenzyl 3-(1-propenyl)-2,2-dimethylcyclopropanecarboxylate.
To preserve the volatile compound in the employed sheet, the compound itself or a solution comprising the compound is impregnated or soaked onto the sheet. The said solution may be any solution wherein the compound is dissolved in any solvent such as acetones and/or alcohols (for example, methanol, ethanol, isopropyl alcohol) and so on. An unlimited amount of the volatile compound may be preserved in the sheet but the object of use, variation of sheet material, variation of compound, and a consideration for the surrounding environment are factors that may influence the amount of preservation. In the situation of utilizing the insecticidal compound of empenthrin, 0.5 to 20 grams of the said insecticidal compound per 1 m2 of sheet surface area (0.5 to 20 g/m2) may be utilized.
The method to incorporate the compound is not limited. The volatile compound may be impregnated or soaked to the sheet(s) before or after the sheets are stacked together.
To produce high results with the present invention, the most outer layering sheet may be separated from the stack, so the inner sheet is left to be exposed to the surrounding environment. The most outer layering sheet tends to loose the ability to vaporize first, and should be separated when vaporization no longer continues in the most outer sheet. Once the outer sheet is separated, the inner sheet wherein a copious amount of the compound still exists, may be exposed to the environment.
The present invention also takes various forms of construction. In the event of constructing the sheets to be a bound stack, an adhesive agent may be disposed on one side of each sheet and a releasing agent may be disposed on the other side. The side wherein the adhesive agent has been disposed may then unite to a side from another sheet in which the releasing agent has been disposed. Free sheets may then be united with the plurality of sheets which have already been united. Accordingly, the most outer layer is made to be easily detachable. A xe2x80x9cmemo pad-like calendarxe2x80x9d which is a construction wherein the sheets are categorized by a day or days and are torn away from the calendar after the day or days pass, is produced in similar fashion.